Understanding Paramagnetism and Haemocyanins

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Questions and Answers

What occurs in antiferromagnetic coupling?

Atoms or molecules are too far apart to couple.

Atoms or molecules try to align in opposite directions. (correct)

Atoms or molecules align in the same direction.

Atoms or molecules orient in random directions.

What role do haemocyanins play in the biological systems of certain organisms?

They synthesize proteins.

They transport oxygen. (correct)

They store energy as fats.

They are involved in muscle contraction.

How is the oxidation state of copper in haemocyanin affected by oxygen binding?

It remains constant at +1.

It changes from +1 to +2. (correct)

It changes from +2 to +3.

It changes from +1 to +3.

What type of magnetic behavior do haemocyanins exhibit?

They are diamagnetic, indicating no lone electrons. Signup and view all the answers

What is the key characteristic of ferromagnetic coupling?

Spins try to orient in the same direction. Signup and view all the answers

What role do transition metals play in biological processes?

They are essential in catalyzing biological reactions. Signup and view all the answers

Which of the following ligands would be expected to rank highest in the spectrochemical series?

NH3 Signup and view all the answers

What is the primary function of haemocyanin in biological systems?

Oxygen transport Signup and view all the answers

Which statement about oxygen transport mechanisms is true?

Haemoglobin can undergo conformational changes to increase oxygen affinity. Signup and view all the answers

What is the electron configuration of Fe3+?

[Ar] 3d5 Signup and view all the answers

In the context of biological molecules, which atom commonly acts as a ligand to transition metals?

Oxygen Signup and view all the answers

Which coupling phenomenon is generally associated with antiferromagnetic interactions in transition metals?

Opposite alignment of spins Signup and view all the answers

What element is commonly used in medical applications for its anticancer properties?

Platinum Signup and view all the answers

What characterizes the diamagnetic nature of the oxymyoglobin complex?

It has no unpaired electrons due to antiferromagnetic coupling. Signup and view all the answers

Which of the following best describes the interaction between unpaired electrons in antiferromagnetic coupling?

They orientate in opposite directions. Signup and view all the answers

Considering the IR stretching frequency, what is the nature of O2 in oxy-Mb?

Superoxide (O2-) Signup and view all the answers

How many unpaired electrons are present in the superoxide state of O2?

One Signup and view all the answers

What is the IR stretching frequency of superoxide (O2-)?

1140 cm-1 Signup and view all the answers

What is a distinguishing feature between ferromagnetic and antiferromagnetic coupling?

Ferromagnetic spins align parallel; antiferromagnetic spins align anti-parallel. Signup and view all the answers

What effect does coupling of unpaired electrons have on overall magnetic properties?

It can lead to either paramagnetic or diamagnetic properties depending on alignment. Signup and view all the answers

Why is the low spin state of Fe3+ associated with one unpaired electron?

Electrons fill lower orbitals first, leaving one unpaired in the higher orbital. Signup and view all the answers

Study Notes

Paramagnetism and Ferromagnetism

Paramagnetism occurs when atoms or molecules are too far apart to couple
Spins are randomly oriented in the absence of a magnetic field
Ferromagnetism occurs when spins orient in the same direction
This is a long-range effect observed in materials like iron magnets
Antiferromagnetism occurs when spins orient in opposite directions and cancel each other out
This is a short-range effect observed in materials like oxygen

Haemocyanins

Haemocyanins are oxygen carriers that are copper-containing proteins
They are found in molluscs and anthropods such as crabs, snails, scorpions, and spiders
The copper(II) binding to oxygen results in blue blood
Horseshoe crabs have a unique haemocyanin with super antibacterial properties and a special clotting agent
This haemocyanin is highly valuable, costing $15,000 per litre

Haemocyanin Oxygen Transfer System

The active site of haemocyanin changes from tetrahedral to square pyramidal upon oxygen binding
Copper is in the +1 oxidation state before oxygen binding and +2 oxidation state after oxygen binding
Haemocyanin is diamagnetic, implying the absence of lone electrons
The oxygen is in the peroxide form, and the spins on the copper atoms couple antiferromagnetically across the peroxide bridge, cancelling each other out

Haemocyanin and Myoglobin

Myoglobin and haemoglobin both have a similar structure to haemocyanin
Myoglobin contains one heme group and is a monomer
Haemoglobin contains four heme groups and is a tetramer
The oxygen in oxy-myoglobin is a superoxide (O2-) evidenced by its IR stretching frequency of 1107 cm-1, which is close to the superoxide IR frequency of 1140 cm-1
This superoxide has one unpaired electron

Oxymyoglobin Complex

Oxymyoglobin is diamagnetic because the unpaired electron in the superoxide couples with the unpaired electron from the Fe3+ in the heme group
This results in an overall diamagnetic complex with no unpaired electrons
The coupling between the superoxide electron and the Fe3+ electron is an example of antiferromagnetic coupling

Transition Metals in Biological Systems

Transition metals play important roles in biological processes and medicine
Ligands bind to transition metals in biological molecules
The function of biological systems can be analyzed using d-orbital splitting and electron configuration

Ligand Types in Biological Molecules

Amino acids containing oxygen in their side-chain can act as ligands to transition metals
Other atoms with lone pairs, such as nitrogen or sulfur, can also act as ligands
Arginine and histidine are strong-field ligands due to their high NH content

Myoglobin and Haemoglobin as Oxygen Carriers

Myoglobin is a monomeric oxygen carrier that binds oxygen in muscle tissue
Haemoglobin is a tetrameric oxygen carrier that transports oxygen in the blood
Haemoglobin comprises two alpha subunits and two beta subunits, which are structurally similar to myoglobin

Iron in Oxy-Myoglobin

Fe3+ in oxy-myoglobin has an electron configuration of [Ar]3d5, with 5 d-electrons
The octahedral structure of oxy-myoglobin results in a low spin state for Fe3+ with only one unpaired electron
The remaining electrons in the d-orbitals fill the lower energy t2g orbitals, and the higher energy eg orbitals remain empty

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Description

This quiz explores the concepts of paramagnetism and ferromagnetism, including their effects and characteristics in various materials. It also covers haemocyanins, their role as oxygen carriers in certain organisms, and their unique properties. Test your knowledge on these fascinating topics in physics and biology.